Distribution frames typically provide that selected incoming or outgoing lines can be "protected", such that internal equipment lines are protected from overvoltage and/or overcurrent conditions. To this end a typical distribution module includes a first "side" for connection to outside lines and a second "side" for connection to internal equipment, with means for connecting and/or protecting the corresponding individual wire connectors on opposing sides. Besides connecting and protecting lines frames are also used as test-points for lines, whereby outside and inside lines and connections may be monitored and tested.
With regard to protection it is desireable that a distribution frame be both flexible as to the kinds of protection it can provide and modular such that protection capacity may be implemented in close accordance with need. With regard to wiring and cross-connection it is of course desireable that access to wire connectors is free and easy, and that connection operations may be accomplished quickly. Last, but not least, it is desireable that a distribution frame accommodate and preferably facilitate the monitoring and testing of lines.